Question

Calculate
(i) The total surface area area and
(ii) Curved surface area
If height is 21 cm and cylinder of radius 14 cm​

Answer 1

Calculate volume of a cylinder:

V = πr2h

(C.S.A)Calculate the lateral surface area of a cylinder (just the curved outside)**:

L = 2πrh

Calculate the top and bottom surface area of a cylinder (2 circles):

T = B = πr2

(T.S.A)Total surface area of a closed cylinder is:

A = L + T + B = 2πrh + 2(πr2) = 2πr(h+r)

Find Out Your Self So Easy Question Put Value And Find Out

Answer 2

Step-by-step explanation:

$\large{\red{\bold{\underline{Given:}}}}$

$\sf \: Radius \: of \: the \: cylinder = 14cm \\ \\ \sf \: Height \: of \: cylinder = 21cm$

$\large{\green{\bold{\underline{To \: Find:}}}}$

$\sf \: (i) \: Total \: surface \: area \: of \: cylinder \\ \\ \sf \: (ii) \: Curved \: surface \: area \: of \: cylinder$

$\large{\blue{\bold{\underline{Formula \: Used:}}}}$

$\sf \: Total \: surface \: area = 2\pi r(r + h) \\ \\ \sf \: Curved \: surface \: area = 2\pi rh$

$\large{\red{\underline\bold{{Solution:}}}}$

$\sf \: Let \: the \: radius \: of \: the \: cylinder \: be \: r, \\ \sf \: and \: the \: height \: of \: the \: cylinder \: as \: h$

$\large{\green{\bold{\underline{Then:}}}}$

$\sf \: (i) \: Total \: surface \: area = 2\pi r(r + h) \\ \\ \rightarrow \: \sf Total \: surface \: area = 2 \times \frac{22}{7} \times 14(14 + 21) \\ \\ \rightarrow \: \sf Total \: surface \: area = 2 \times \frac{22}{7} \times 14(35) \\ \\ \rightarrow \: \sf \: Total \: surface \: area = \frac{44}{\cancel7} \times \cancel14 \times 35 \\ \\ \rightarrow \: \sf \: Total \: surface \: area = 3080 \: {cm}^{2}$

$\large{\pink{\bold{\underline{Now:}}}}$

$\sf \: (ii) \: Curved \: surface \: area = 2\pi rh \\ \\ \rightarrow \: \sf \: Curved \: surface \: area = 2 \times \frac{22}{7} \times 14 \times 21 \\ \\ \rightarrow \: \sf \: Curved \: surface \: area = 2 \times \frac{22}{\cancel7} \times \cancel14 \times 21 \\ \\ \rightarrow \: \sf \: Curved \: surface \: area = 44 \times 2 \times 21 \\ \\ \rightarrow \: \sf \: Curved \: surface \: area = 1848 \: {cm}^{2}$

$\large{\orange{\bold{\underline{Therefore:}}}}$

$\sf \: The \: total \: surface \: area \: of \: cylinder \: is \\ \sf \: 3080 {cm}^{2} \: and \: curved \: surface \: area \: is \: 1848 {cm}^{2}.$